(a) An existing Group 1 or Group 2 POTW treatment plant must comply with the initial notification requirements in §63.1591(a).

(b) Cover and control standard. Except as provided in paragraph (c) of this section, new Group 1 and Group 2 POTW treatment plants must install covers on the emission points up to, but not including, the secondary influent pumping station or the secondary treatment units. These emission points are treatment units that include, but are not limited to, influent waste stream conveyance channels, bar screens, grit chambers, grinders, pump stations, aerated feeder channels, primary clarifiers, primary effluent channels, and primary screening stations. In addition, all covered units, except primary clarifiers, must have the air in the headspace underneath the cover ducted to a control device in accordance with the standards for closed-vent systems and control devices in §63.693 of subpart DD—National Emission Standards for Hazardous Air Pollutants from Off-site Waste and Recovery Operations of this part, except you may substitute visual inspections for leak detection rather than Method 21 of appendix A-7 of part 60 of this chapter. Covers must meet the following requirements:

(1) Covers must be tightly fitted and designed and operated to prevent exposure of the wastewater to the atmosphere. This includes, but is not limited to, the absence of visible cracks, holes, or gaps in the roof sections or between the roof and the supporting wall; broken, cracked, or otherwise damaged seals or gaskets on closure devices; and broken or missing hatches, access covers, caps, or other closure devices.

(2) If wastewater is in a treatment unit, each opening in the cover must be maintained in a closed, sealed position, unless plant personnel are present and conducting wastewater or sludge sampling, or equipment inspection, maintenance, or repair.

(c) HAP fraction emitted standard. As an alternative to the requirements in paragraph (b) of this section, a new Group 1 and Group 2 POTW treatment plant may comply by demonstrating, for all emission points up to, but not including, the secondary influent pumping station or the secondary treatment units, that the annual rolling average HAP fraction emitted (calculated as specified in §63.1588(c)(3)) does not exceed 0.014. You must demonstrate that for your POTW treatment plant, the sum of all HAP emissions from these units divided by the sum of all HAP mass loadings to the POTW treatment plant results in an annual rolling average of the HAP fraction emitted of no greater than 0.014. You may use any combination of pretreatment, wastewater treatment plant modifications, and control devices to achieve this performance standard.

(d) At all times, the POTW must operate and maintain any affected source, including associated air pollution control equipment and monitoring equipment, in a manner consistent with safety and good air pollution control practices for minimizing emissions. The general duty to minimize emissions does not require the POTW to make any further efforts to reduce emissions if the requirements of the applicable standard have been met. Determination of whether a source is operating in compliance with operation and maintenance requirements will be based on information available to the Administrator, which may include, but is not limited to, monitoring results, review of operation and maintenance procedures, review of operation and maintenance records, and inspection of the source.